The discovery of stainless steel and the development of carbon steel reinforcing bar are, in many ways, very similar. They both have lives beginning early in the twentieth century and are now perceived as being at the developed stage of their product life cycle. However it is at this point that the differences in performance of the two products must be considered. Reinforced concrete structures using conventional carbon steel reinforcement are now known to be inadequate when subjected to corrosive environments. Stainless steel reinforcing bar is technically successful and has been used by direct substitution for carbon steel to achieve long life in these corrosive environments. Examples are given showing the need to correctly specify materials to suit the desired life span of the structure and the environment the structure will be subjected to. These clearly outline the limitations of carbon steel reinforcement in comparison with stainless steel when used within structures designed for long life in aggressive environments. The virtues of stainless steel for constructional application are well established. The technical advantage of stainless steel is proven and life spans exceeding 120 years (Ref 1) are predictable. Current restraint to greater usage is the initial high cost, unavailability and a lack of empathy between specifier, buyer and supplier. Attempts to find a low cost traditional route to make stainless steel rebar were unsuccessful. A new innovative manufacturing process was developed based on precision weld depositing ribs and on to plato round stainless steel bar. This process produces rebar, fine and coarse threads in any variation and combination in compliance with the relevant specification. Weight savings of up to 40 percent are achieved without any reduction in strength compared with conventionally machined stainless steel bar products.
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